Diaphragm pumps are used for many important applications and are often vital components of gasoline engines with one-inch cylinders. This particular model features four diaphragms with a mounting rail, pulsation dampener, and a six spline male PTO shaft measuring 1 3/8-inches. The Udor RO series has glass-filled nylon manifolds and plasticized aluminum heads. Control units are not included with this pump.